JP4567214B2

JP4567214B2 - Pipe fitting

Info

Publication number: JP4567214B2
Application number: JP2001027484A
Authority: JP
Inventors: 和史大橋; 栄治磯部; 牧赤塚; 聡斉藤
Original assignee: 株式会社ベンカン・ジャパン
Priority date: 2001-02-02
Filing date: 2001-02-02
Publication date: 2010-10-20
Anticipated expiration: 2021-02-02
Also published as: JP2002228062A

Description

【０００１】
【発明の属する技術分野】
本発明は、給水、給湯、冷温水配管等に使用されるステンレス鋼管、銅管等の金属管をその端部に拡管加工により形成された環状突出部を利用して接続するために用いる管継手に関する。
【０００２】
【従来の技術】
従来、この種の管継手として、実開昭６３−１４５０８９号公報、特開平１０−３１８４５９号公報等に記載されているような構成が知られている。これらの従来例について概略説明すると、薄肉のステンレス鋼管の端部に拡管加工により断面において、山型、若しくは円弧状の環状突出部が形成されている。継手本体の端部内側には環状のシール材収容凹所が形成され、このシール材収容凹所にシール材が収容されている。そして、ステンレス鋼管の端部が継手本体の内部に挿入され、継手本体の端部外周に形成された雄ねじ部にステンレス鋼管に嵌合されているナットの雌ねじ部が螺合され、ナットの内側に形成されている係合部によりステンレス鋼管の環状突出部における管端に対する離隔側部が加圧されてステンレス鋼管が前進される。これに伴い、ステンレス鋼管の環状突出部における管端側部でシール材の内側面を加圧し、シール材を継手本体のシール材収容凹所とステンレス鋼管の環状突出部との間に圧縮状態に介在させ、ステンレス鋼管をシール状態で接続するように構成されている。
【０００３】
【発明が解決しようとする課題】
しかしながら、前記のような従来例の構成では、ステンレス鋼管の環状突出部における管端に対する離隔側部をナットの係合面で押圧してステンレス鋼管を前進させながらナットの雌ねじ部を継手本体の雄ねじ部に螺合するため、ナットとステンレス鋼管の環状突出部との摩擦抵抗によってステンレス鋼管がナットの回転方向に共回りするおそれがある。この共回りが発生すると、ステンレス鋼管の環状突出部で圧縮されるシール材および継手本体がステンレス鋼管と一体に回転し、継手本体の他側に既に前記と同様にしてステンレス鋼管をナットで接続している場合には、このナットが継手本体に対して緩んでしまうことがあり、接続の信頼性に劣る。また、シール材がステンレス鋼管の環状突出部との摩擦抵抗により損傷するおそれがあり、この点においても接続の信頼性に劣る。
【０００４】
本発明の目的は、前記のような従来例の問題を解決するものであって、ナットにより金属管を継手本体にシール状態で接続する際、金属管がナットと共回りするのを防止することができ、したがって、継手本体の他側に螺合されているナット等が緩んだり、シール材が損傷するのを防止することができて接続の信頼性を向上させることができるようにした管継手を提供しようとするものである。
【０００５】
本発明の他の目的は、ナットと金属管の共回りを防止する滑り部材がナットから脱落し、更には紛失するのを防止することができ、したがって、作業現場における接続作業を簡単に、かつ迅速に行うことができるようにした管継手を提供しようとするものである。
【０００６】
【課題を解決するための手段】
本発明の一形態にかかる管継手は、管端側から離隔側に至るに従い、次第に大径となり、大径部に続いて次第に小径となる環状突出部を有する金属管を接続する管継手であって、端部外周に雄ねじ部を有する継手本体と、前記金属管の外周に嵌合され、前記継手本体の雄ねじ部に螺合する雌ねじ部を有するナットと、前記ナットの内側において管挿入方向の前方に解放された滑り部材収容凹所にナットと一体に前進し得るように設けられ、内側に前端側から後端側へ向かって次第に小径となるようなテーパ状の係合面を有するとともに、その外側と後端側が滑り部材収容凹所に支持され、ナットの雌ねじ部を前記継手本体の雄ねじ部に螺合することにより、前記金属管の環状突出部における管端に対する離隔側部を加圧して前記金属管を前進させる樹脂製の滑り部材と、継手本体の内側面に形成されるシール収容凹所に嵌合され、前記金属管の前進に伴い、少なくとも前記継手本体と前記金属管の環状突出部における管端側部との間に圧縮状態で介在され、その外側と管端側とがシール収容凹所に支持される、シール材とを備え、前記管の外側においてナットと継手本体とを羅合した際に、管の外側であって環状突出部の管端側にシール材が、管の外側であって環状突出部の離隔側に滑り部材が、当接され、ナットと継手本体との羅合による軸方向の圧縮力によって、シール収容凹所において内側及び離隔側に押されることにより、シール材が環状突出部の管端側に対して圧接されることを特徴とする。
【０００７】
前記課題を解決するために本発明の他の管継手は、前記管継手において、前記継手本体における雄ねじ部の終端部に嵌合され、前記ナットの手締めを妨げ、前記ナットの工具による本締めの際には変形する突出部を有し、前記ナットの工具による本締めの際、前記ナットの先端部内側に隠されるストップリングを備えたものである。
【０００８】
前記各管継手において、前記滑り部材を前記ナットに接着により一体的に設けることができ、または前記滑り部材を前記ナットの溝状の収容凹所に嵌合して前記ナットに保持させることができ、または前記滑り部材を前記ナットの溝状の収容凹所に嵌合するとともに接着して前記ナットと一体的に設けることができる。
【０００９】
前記滑り部材としては、連続するリング状に連続したもの、または１箇所に切り離し部を有し、外力により弾性変形して径が縮小され、外力が除かれることにより径が拡大するように復元されるリング状に形成したものを用いることもできる。
【００１０】
前記各管継手において、前記継手本体が、端部の拡開部にシール材収容凹所を有し、このシール材収容凹所にシール材を収容し、前記ナットの雌ねじ部を前記継手本体の雄ねじ部に螺合して前記ナットの内側の滑り部材により前記金属管の環状突出部における管端に対する離隔側部を加圧することにより、前記環状突出部における管端側部を前記シール材に加圧するとともに、前記継手本体の拡開部における基端部に加圧するように構成することができる。
【００１１】
前記のように構成された本発明によれば、金属管の端部を継手本体に挿入し、金属管に嵌合しているナットの雌ねじ部を継手本体の雄ねじ部に螺合し、ナットの内側に設けている滑り部材を介して金属管の環状突出部における管端に対する離隔側部を加圧して金属管を前進させ、これに伴い、少なくとも継手本体と金属管の環状突出部における管端側部とでシール材を加圧し、金属管と継手本体とをシール状態で接続することができる。このように、端部に環状突出部を有する金属管をナットにより継手本体にシール状態で接続する際、滑り部材を介して金属管を継手本体に対して前進させるので、金属管がナットと共回りするのを防止することができる。
【００１２】
【発明の実施の形態】
以下、本発明の実施形態について図面を参照しながら説明する。
まず、本発明の第１の実施形態について説明する。図１は本発明の第１の実施形態に係る管継手を示し、接続前の状態の要部断面図、図２は同管継手を示し、接続後の状態の要部断面図、図３（ａ）、（ｂ）はそれぞれ同管継手に用いる滑り部材を示す正面図、右側面図、図４（ａ）、（ｂ）はそれぞれ同管継手に用いるストップリングを示す正面図、右側面図である。
【００１３】
本実施形態においては、金属管として薄肉のステンレス鋼管を用い、このステンレス鋼管と管継手を接続する例を示し、図１、図２においては、一方のステンレス鋼管を継手本体の一側に接続する状態を示し、他方のステンレス鋼管を継手本体の他側に接続する状態を図示省略している。
【００１４】
図１および図２に示すように、薄肉のステンレス鋼管１に管端よりやや内方に位置して拡管加工により環状突出部２が形成される。その一例として、ステンレス鋼管１の端部内側に環状でゴム製の拡管部材が挿入され、この拡管部材が外周方向へ膨張されることにより、ステンレス鋼管１が均一な圧力で拡管加工される。このような拡管加工により環状突出部２は管端側から離隔側に至るに従い、次第に大径となり、大径部に続いて次第に小径となる断面円弧状に形成されている。
【００１５】
継手本体３はステンレス等の金属製で、端部の挿入部４がステンレス鋼管１における環状突出部２の先方を挿入することができる内径に形成され、挿入部４の基部は小径に形成されてステンレス鋼管１の過剰な挿入を規制するストッパ部５として形成され、挿入部４の先方内側にステンレス鋼管１の環状突出部２における管端側を挿入することができるように先端側に至るに従い、次第に大径となるテーパー状に傾斜する拡開部６が形成され、この拡開部６における挿入部４側寄り位置にシール材収容凹所７が形成されている。この収容凹所７は、図示例では環状溝として形成され、シール材であるＯリング８が離脱防止された係合状態で収容されている。そして、Ｏリング８は収容凹所７に収容された状態で、その内径寸法が接続されるステンレス鋼管１の拡管加工される前の外径より大きくなるように設定されている。継手本体３の端部外周面には雄ねじ部９が形成されている。継手本体３には雄ねじ部９の終端および中間部の鍔部１０に隣接して環状の収容溝１１が形成されている。
【００１６】
ナット１２としては、基部内側が小径となり、中間部内側が中間径となり、先端部内側が大径となるステンレス等の金属製の袋ナット（ユニオンナット）が用いられている。ナット１２の基部内側には環状収容凹所１３が形成され、この収容凹所１３は前方が開放され、軸心とほぼ平行な環状穴壁から成る段差部１４と、この段差部１４と直角方向で内方に突出する係合部１５とにより形成されている。ナット１２の中間部内側には継手本体３の雄ねじ部９に螺合し得る雌ねじ部１６が形成され、ナット１２の先端部は外被筒１７として形成されている。ナット１２における基部と中間部との間、中間部と先端部との間にはそれぞれ軸心と直角方向の面から成る当接面１８、押圧面１９が形成されている。
【００１７】
滑り部材２０は、ＰＴＦＥ（ポリテトラフルオロエチレン樹脂）、ＰＦＡ（パーフロロアルコキシ樹脂）、ポリアミド樹脂、ポリブチレンテレフタレート樹脂等の低摩擦係数の合成樹脂等から成り、図１ないし図３に示すように、全体として連続するリング状に形成され、外周面が軸心とほぼ平行な環状面となり、後端面が軸心とほぼ直角方向の面となり、内側が前端から後端側へ向かって次第に小径となるようなテーパー状の係合面２１に形成され、係合面２１の後側が軸心とほぼ平行な面となるように形成されている。この滑り部材２０はナット１２の収容凹所１３に収容され、外周面が段差部１４に接着剤２２により接着され、後端面が係合部１５に係合され、ナット１２と一体的に前進されるようになっている。これらナット１２および滑り部材２０がステンレス鋼管１の外周に軸方向に沿って移動可能に遊合状態で嵌合されるようになっている。
【００１８】
色付きのストップリング２３は、ポリアセタール樹脂等から成り、特に、図４（ａ）、（ｂ）から明らかなようにリング状部２４の一側外周にほぼ等角度間隔で軸心方向に突出する突出部２５が一体に設けられ、リング状部２４の１箇所が切り離し部２６により切り離され、外力により弾性変形されて径が拡大され、外力が除かれることにより径が縮小するように復元されるようになっている。このストップリング２３はそのリング状部２４が継手本体３の収容溝１１に収められ、突出部２５が雄ねじ部９における収容溝１１側寄りの外周において、雄ねじ部９とに隙間を存して嵌合されている。このとき、ストップリング２３は前記のように切り離し部２６により拡開し得るので、そのリング状部２４を雄ねじ部９に容易に通過させて収容溝１１に容易に収容することができる。
【００１９】
そして、ナット１２をステンレス鋼管１に嵌合した状態で、その雌ねじ部１６を継手本体３の雄ねじ部９に螺合することにより、滑り部材２０における傾斜した係合面２１によりステンレス鋼管１の環状突出部２における管端に対する離隔側部を加圧してステンレス鋼管１を前進させることができる。これに伴い、ステンレス鋼管１の環状突出部２における管端側部をＯリング８に圧接させてＯリング８を収容凹所７の底部側へ加圧させ、Ｏリング８を収容凹所７の底部と環状突出部２における管端側部とで継手本体３およびステンレス鋼管１の軸心に対して傾斜方向で圧縮させることができるようになっている。
【００２０】
また、ナット１２の継手本体３に対する締め込みに際し、手締めの場合には押圧面１９がストップリング２３の突出部２５に当接した状態から突出部２５が変形されず、すなわち、ナット１２および滑り部材２０によりステンレス鋼管１を前進させることができず、工具による本締めの場合には押圧面１９によりストップリング２３の突出部２５を変形させることができる、すなわち、ナット１２および滑り部材２０によりステンレス鋼管１を前記のように前進させることができるように設定されている。この変形した突出部２５はナット１２の外被筒１７の内側に隠蔽されるようになっている。また、ナット１２および滑り部材２０により前記のようにステンレス鋼管１を前進させ、Ｏリング８を圧縮させた連続状態で環状突出部２の管端側部における基部が継手本体３の挿入部４と拡開部６との角部に２７に加圧状態で当接され、ナット１２の当接部１８が継手本体３の先端面に当接されるようになっている。
【００２１】
以上の構成において、以下、ステンレス鋼管１と継手本体３との接続動作について説明する。まず、図１に示すように、ステンレス鋼管１に、１個、若しくは２個のナット１２および滑り部材２０を嵌合し、ステンレス鋼管１の一端部、若しくは両端部において、管端よりやや内方に位置して前記のように管径を拡開する拡管加工を行い、断面円弧状の環状突出部２を形成する。次に、ステンレス鋼管１における環状突出部２の先方を継手本体３の挿入部４に挿入する。次に、ステンレス鋼管１に嵌合してあるナット１２を滑り部材２０と共に手で回してナット１２の雌ねじ部１６を継手本体３の雄ねじ部９に螺合し、雌ねじ部１６の先端外周側に位置する押圧面１９をストップリング２３の突出部２５の先端面に当接させる。
【００２２】
次に、工具を用いてナット１２を滑り部材２０と共に図２に示すように締め込んで、ナット１２の押圧面１９によりストップリング２３の突出部２５を押圧して押し潰しながら滑り部材２０の係合面２１によりステンレス鋼管１の環状突出部２における管端に対する離隔側部を押圧してステンレス鋼管１を前進させる。ステンレス鋼管１の前進に伴い、ステンレス鋼管１の環状突出部２における管端側部でＯリング８を収容凹所７の底部に対して加圧し、環状突出部２における管端側の基部を継手本体３の角部２７に圧接する。ここで、環状突出部２における管端側部のＯリング８に対する摩擦抵抗と角部２７に対する摩擦抵抗との和が滑り部材２０の係合面２１と環状突出部２における管端に対する離隔側部との摩擦抵抗より大きくなるように設定しておくことにより、ナット１２を滑り部材２０と共に回転させてナット１２を継手本体３に締め付ける際にステンレス鋼管１の共回りを防止することができる。
【００２３】
このようにしてナット１２における当接面１８が継手本体３の先端面に当接するまでナット１２の雌ねじ部１６を継手本体３の雄ねじ部９に螺合することにより、ステンレス鋼管１の環状突出部２における管端側部と収容凹所７の底部とでＯリング８を継手本体３およびステンレス鋼管１の軸心に対する傾斜方向で圧縮させるので、継手本体３とステンレス鋼管１とを完全なシール状態に接続し、ステンレス鋼管１内を流れる流体の漏洩が防止することができる。このようにステンレス鋼管１と継手本体３を接続した際、Ｏリング８は収容凹所７の底部と環状突出部２における管端側部のほぼ二面で強く圧接されるので、Ｏリング８の圧縮永久歪が小さく、復元性を十分に備えることができ、したがって、ステンレス鋼管１と継手本体３との間のシールを半永久的に確保することができ、極めてシール性に優れる。
【００２４】
また、ステンレス鋼管１と継手本体３との接続作業において、ナット１２の締め込みが確実に行われ、接続されたか否かについては、色付きのストップリング２３の平行な突出部２５が図２に示すようにナット１２の押圧面１９により押し潰され、かつ外被筒１７の内側に隠蔽されて見えなくなることにより、ナット１２の締め込みが確実に行われ、確実に接続されたことを確認することができる。
【００２５】
継手本体３に拡管加工されていないステンレス鋼管１が作業者の不注意によって配管施工されたとしても、前記のようにＯリング８の内周と拡管加工されていないステンレス鋼管１の外周との間には隙間があるので（図１参照）、配管施工後の水圧試験時に水漏れが発生するので、直ちに手直し工事で修理することができる。
【００２６】
そして、配管施工後、水圧（空圧）試験を行ってステンレス鋼管１と継手本体３との接続部のシール検査を行うと、前記のように完全なシール状態で接続されている場合には、水（空気）漏れしないが、万一、ナット１２の締め忘れ等の不備があった場合には、図１に示すＯリング８の内周面とステンレス鋼管１の外周面との隙間を通って外部に水（空気）が漏れるので、配管接続の不備を発見でき、完全な配管接続を行うことができる。
【００２７】
前記第１の実施形態においては、滑り部材２０をナット１２の収容凹所１３に接着により一体的に設けているので、ナット１２にステンレス鋼管１を挿通させる際、滑り部材２０がナット１２より脱落して紛失するのを防止することができ、したがって、配管作業を円滑に、かつ迅速に行うことができる。
【００２８】
次に、本発明の第２の実施形態について説明する。図５は本発明の第２の実施形態に係る管継手を示し、接続前の状態の要部断面図、図６は同管継手を示し、接続後の状態の要部断面図、図７（ａ）、（ｂ）はそれぞれ同管継手に用いる滑り部材を示す正面図、右側面図である。
【００２９】
本実施形態においては、前記第１の実施形態とは滑り部材２０をナット１２に一体的に設ける構成において差異を有し、その他の構成においては同じであるので、同じ部分には同じ符号を付してその説明を省略し、主として異なる構成について説明する。
【００３０】
本実施形態においては、図５ないし図７に示すように、ナット１２の基部内側に環状溝からなる収容凹所２８が形成されている。一方、滑り部材２９は、低摩擦係数の合成樹脂から成り、全体としてリング状に形成されるが、１箇所に切り離し部３０を有し、外力により弾性変形して径が縮小され、外力が除かれることにより径が拡大するように復元される構成となっている。この滑り部材２９は、その外周面と前端面と後端面とが収容凹所２８の形状に適合し得るように形成され、内側が前端から後端側へ向かって次第に小径となるようなテーパー状の係合面３１に形成され、係合面３１の後側が軸心とほぼ平行な面となるように形成されている。この滑り部材２９は、外力による弾性変形により径が縮小され、ナット１２の収容凹所２８にその前側の低い突出部側から挿入され、外力が除かれることにより収容凹所２８内で拡開されて離脱しないように保持されている。
【００３１】
そして、ナット１２および滑り部材２９をステンレス鋼管１に遊合状態に嵌合した状態で、ナット１２の雌ねじ部１６を継手本体３の雄ねじ部９に螺合することにより、滑り部材２９における傾斜した係合面３１によりステンレス鋼管１の環状突出部１２における管端に対する離隔側部を加圧してステンレス鋼管１を前進させ、前記第１の実施形態と同様に、継手本体３とステンレス鋼管１とをシール状態で接続することができる。
【００３２】
本実施形態においても、環状突出部２における管端側部のＯリング８に対する摩擦抵抗と角部２７に対する摩擦抵抗との和が滑り部材２９の係合面３１と環状突出部２における管端に対する離隔側部との摩擦抵抗より大きくなるように設定しておくことにより、ナット１２を回転させてナット１２を継手本体３に締め付ける際にステンレス鋼管１の共回りを防止することができる。そして、特に、本実施形態のように滑り部材２９をナット１２における環状溝から成る収容凹所２８に収容してナット１２に保持することにより、滑り部材２９がナット１２に対して回転し得るので、ステンレス鋼管１の環状突出部２における管端に対する離隔側がナット１２の継手本体３に対する締め付け時に滑り部材２９を介して押圧する際の摩擦抵抗を更に一層、小さくすることができる。
【００３３】
なお、前記第１の実施形態においても滑り部材２０を前記第２の実施形態と同様、１箇所に切り離し部を有するように構成することができる。また、第１、第２の実施形態のいずれにおいても滑り部材２０、２８を二つ割等の割型に構成することもできる。また、第２の実施形態における滑り部材２９は環状溝からなる収容凹所２８に収容するとともに接着によりナット１２と一体的に設けることもできる。また、滑り部材２９を分割することなく、環状に形成することもでき、この場合、例えば、収容凹所２８を形成する壁部の一方をナット１２に螺着するようにすれば、滑り部材２９を収容凹所２８に簡単に収容することができる。また、前記第１の実施形態における滑り部材２０は収容凹所１３に接着することなく、単に収容してもよい。また、ステンレス鋼管１の環状突出部２における管端側部とシール材との摩擦抵抗を環状突出部２における管端に対する離隔側部と滑り部材２０、２８との摩擦抵抗より大きくなるように設定することにより、環状突出部２における管端側部を継手本体３の角部２７に圧接させなくてもよい。更に、Ｏリング８等のシール材は先端側を開放した収容凹所に収容し、このシール材をステンレス鋼管１の環状突出部２のみでなく、ナット１２の当接面１８により加圧することもできる。このほか、本発明は、その基本的技術思想を逸脱しない範囲で種々設計変更することができる。
【００３４】
【発明の効果】
以上説明したように本発明によれば、金属管の端部を継手本体に挿入し、金属管に嵌合しているナットの雌ねじ部を継手本体の雄ねじ部に螺合し、ナットの内側に設けている滑り部材を介して金属管の環状突出部における管端に対する離隔側部を加圧して金属管を前進させ、これに伴い、少なくとも継手本体と金属管の環状突出部における管端側部とでシール材を加圧し、金属管と継手本体とをシール状態で接続することができる。このように、端部に環状突出部を有する金属管をナットにより継手本体にシール状態で接続する際、滑り部材を介して金属管を継手本体に対して前進させるので、金属管がナットと共回りするのを防止することができる。したがって、継手本体の他側に螺合されているナット等が緩んだり、シール材が損傷するのを防止することができて接続の信頼性を向上させることができる。
【００３５】
また、滑り部材をナットに一体的に設け、若しくは離脱防止可能に保持することにより、ナットに金属管を挿通させる際に滑り部材の脱落、紛失を防止することができ、したがって、接続作業を円滑に、かつ迅速に行うことができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態に係る管継手を示し、接続前の状態の要部断面図である。
【図２】同管継手を示し、接続後の状態の要部断面図である。
【図３】（ａ）、（ｂ）はそれぞれ同管継手に用いる滑り部材を示す正面図、右側面図である。
【図４】（ａ）、（ｂ）はそれぞれ同管継手に用いるストップリングを示す正面図、右側面図である。
【図５】本発明の第２の実施形態に係る管継手を示し、接続前の状態の要部断面図である。
【図６】同管継手を示し、接続後の状態の要部断面図である。
【図７】（ａ）、（ｂ）はそれぞれ同管継手に用いる滑り部材を示す正面図、右側面図である。
【符号の説明】
１ステンレス鋼管（金属管）
２環状突出部
３継手本体
８Ｏリング（シール材）
１２ナット
１３収容凹所
２０滑り部材
２１係合面
２３ストップリング
２８収容凹所
２９滑り部材
３１係合面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe joint used for connecting a metal pipe such as a stainless steel pipe, a copper pipe or the like used for water supply, hot water supply, cold / hot water pipes, etc. to an end portion thereof by using an annular protrusion formed by pipe expansion processing. About.
[0002]
[Prior art]
Conventionally, as this type of pipe joint, a configuration as described in Japanese Utility Model Laid-Open No. 63-145089, Japanese Patent Laid-Open No. 10-318459, and the like is known. Briefly explaining these conventional examples, a mountain-shaped or arc-shaped annular projecting portion is formed in a cross section at the end of a thin stainless steel pipe by pipe expansion processing. An annular seal material accommodation recess is formed inside the end of the joint body, and the seal material is accommodated in the seal material accommodation recess. Then, the end of the stainless steel pipe is inserted into the inside of the joint body, and the female thread part of the nut fitted to the stainless steel pipe is screwed into the male thread part formed on the outer periphery of the end of the joint body. The formed engaging portion pressurizes the remote side portion of the annular projecting portion of the stainless steel tube with respect to the tube end to advance the stainless steel tube. Along with this, the inner surface of the sealing material is pressurized at the pipe end side portion of the annular projecting portion of the stainless steel pipe, and the sealing material is compressed between the sealing material receiving recess of the joint body and the annular projecting portion of the stainless steel pipe. The stainless steel pipe is interposed and connected in a sealed state.
[0003]
[Problems to be solved by the invention]
However, in the configuration of the conventional example as described above, the female threaded portion of the nut is connected to the male thread of the joint body while the stainless steel tube is advanced by pressing the separation side portion with respect to the tube end of the annular projecting portion of the stainless steel tube with the engaging surface of the nut. Therefore, the stainless steel pipe may rotate in the rotation direction of the nut due to the frictional resistance between the nut and the annular protrusion of the stainless steel pipe. When this co-rotation occurs, the seal material compressed by the annular protrusion of the stainless steel pipe and the joint body rotate together with the stainless steel pipe, and the stainless steel pipe is already connected to the other side of the joint body with a nut in the same manner as described above. If this is the case, the nut may loosen with respect to the joint body, resulting in poor connection reliability. Further, the sealing material may be damaged due to frictional resistance with the annular projecting portion of the stainless steel pipe, and in this respect, the connection reliability is poor.
[0004]
An object of the present invention is to solve the problems of the conventional example as described above, and to prevent the metal tube from rotating together with the nut when the metal tube is connected to the joint body in a sealed state by the nut. Therefore, it is possible to prevent loosening of nuts and the like screwed on the other side of the joint body and damage to the sealing material, and to improve the connection reliability. Is to provide.
[0005]
Another object of the present invention is to prevent the sliding member that prevents the nut and the metal tube from rotating together from falling out of the nut and further losing them. An object of the present invention is to provide a pipe joint that can be quickly performed.
[0006]
[Means for Solving the Problems]
A pipe joint according to one aspect of the present invention is a pipe joint that connects a metal pipe having an annular projecting portion that gradually increases in diameter from the pipe end side to the remote side and then gradually decreases in diameter after the large diameter part. A fitting main body having a male threaded portion on the outer periphery of the end, a nut having a female threaded portion that is fitted on the outer periphery of the metal tube and is screwed into the male threaded portion of the joint main body, and a tube insertion direction inside the nut. The sliding member receiving recess that is released forward is provided so as to be able to advance integrally with the nut, and has a tapered engagement surface that gradually becomes smaller in diameter from the front end side toward the rear end side, The outer side and the rear end side are supported by the sliding member housing recess, and the female threaded portion of the nut is screwed into the male threaded portion of the joint body, thereby pressing the remote side portion with respect to the tube end of the annular projecting portion of the metal tube. Forward the metal tube A sliding member made of a resin to be fitted, and a seal receiving recess formed on the inner surface of the joint main body, and at least the pipe end side of the annular protrusion of the joint main body and the metal pipe as the metal pipe advances A sealing material that is interposed in a compressed state and is supported by a seal housing recess on the outer side and the pipe end side, and when the nut and the joint body are joined together outside the pipe A seal member is abutted on the tube end side of the annular projection portion outside the tube, and a sliding member is abutted on the remote side of the annular projection portion on the outer side of the tube. The seal member is pressed against the tube end side of the annular projecting portion by being pushed toward the inner side and the separated side in the seal housing recess by the compressive force in the direction.
[0007]
In order to solve the above-mentioned problems, another pipe joint of the present invention is fitted to the end part of the male thread part of the joint body in the pipe joint to prevent manual tightening of the nut, In this case, it has a projecting portion that deforms, and is provided with a stop ring that is hidden inside the front end portion of the nut when the nut is tightened with a tool.
[0008]
In each of the pipe joints, the sliding member can be provided integrally with the nut by bonding, or the sliding member can be fitted into the groove-shaped receiving recess of the nut and held by the nut. Alternatively, the sliding member can be integrally provided with the nut by fitting and adhering to the groove-shaped accommodation recess of the nut.
[0009]
The sliding member has a continuous ring shape, or has a cut-out portion at one location, and is elastically deformed by an external force to reduce the diameter, and is restored so that the diameter is increased by removing the external force. It is also possible to use one formed in a ring shape.
[0010]
In each of the pipe joints, the joint body has a seal material housing recess in the widened portion of the end, the seal material is housed in the seal material housing recess, and the female thread portion of the nut is connected to the joint body. The pipe end side portion of the annular projecting portion is added to the sealing material by being screwed into the male thread portion and pressurizing the separation side portion with respect to the tube end of the annular projecting portion of the metal tube by the sliding member inside the nut. While pressing, it can comprise so that the base end part in the expansion part of the said joint main body may be pressurized.
[0011]
According to the present invention configured as described above, the end portion of the metal tube is inserted into the joint body, the female thread portion of the nut fitted in the metal tube is screwed into the male thread portion of the joint body, The metal tube is advanced by pressurizing the separation side portion of the annular projection of the metal tube with respect to the tube end via the sliding member provided on the inner side, and at the same time, at least the tube end of the joint body and the annular projection of the metal tube The sealing material can be pressurized with the side portion, and the metal tube and the joint body can be connected in a sealed state. Thus, when a metal tube having an annular protrusion at the end is connected to the joint body in a sealed state using a nut, the metal tube is advanced with respect to the joint body via the sliding member. It is possible to prevent turning.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a first embodiment of the present invention will be described. FIG. 1 shows a pipe joint according to the first embodiment of the present invention, and is a cross-sectional view of the main part before connection, FIG. 2 is a cross-sectional view of the main part in the state after connection, showing the pipe joint, FIG. FIGS. 4A and 4B are a front view and a right side view showing a sliding member used for the pipe joint, and FIGS. 4A and 4B are a front view and a right side view showing a stop ring used for the pipe joint. It is.
[0013]
In the present embodiment, an example in which a thin stainless steel pipe is used as a metal pipe and the stainless steel pipe is connected to a pipe joint is shown. In FIGS. 1 and 2, one stainless steel pipe is connected to one side of the joint body. The state is shown, and the state in which the other stainless steel pipe is connected to the other side of the joint body is not shown.
[0014]
As shown in FIGS. 1 and 2, an annular protrusion 2 is formed on a thin stainless steel pipe 1 by a tube expansion process located slightly inward from the pipe end. As an example, an annular rubber tube expansion member is inserted inside the end portion of the stainless steel tube 1, and the tube expansion member is expanded in the outer peripheral direction, whereby the stainless steel tube 1 is expanded with a uniform pressure. By such tube expansion processing, the annular projecting portion 2 is formed in a circular arc shape that gradually increases in diameter from the tube end side to the remote side and gradually decreases in size after the large diameter portion.
[0015]
The joint body 3 is made of metal such as stainless steel, and the insertion portion 4 at the end is formed with an inner diameter that allows the tip of the annular projection 2 in the stainless steel pipe 1 to be inserted, and the base of the insertion portion 4 is formed with a small diameter. It is formed as a stopper portion 5 that restricts excessive insertion of the stainless steel pipe 1, and as it reaches the distal end side so that the pipe end side of the annular projecting portion 2 of the stainless steel pipe 1 can be inserted inside the insertion portion 4, A widening portion 6 that gradually increases in taper and has a larger diameter is formed, and a sealing material accommodation recess 7 is formed at a position closer to the insertion portion 4 in the widening portion 6. The housing recess 7 is formed as an annular groove in the illustrated example, and is housed in an engaged state in which an O-ring 8 that is a sealing material is prevented from being detached. The O-ring 8 is set so that the inner diameter of the O-ring 8 is larger than the outer diameter of the connected stainless steel pipe 1 before being expanded. A male screw portion 9 is formed on the outer peripheral surface of the end portion of the joint body 3. An annular receiving groove 11 is formed in the joint body 3 adjacent to the terminal end of the male screw portion 9 and the flange portion 10 in the middle portion.
[0016]
As the nut 12, a cap nut (union nut) made of metal such as stainless steel having a small diameter inside the base, an inside diameter at the middle and a large diameter inside the tip is used. An annular receiving recess 13 is formed on the inner side of the base of the nut 12. The receiving recess 13 is open at the front and has a stepped portion 14 formed of an annular hole wall substantially parallel to the axis, and a direction perpendicular to the stepped portion 14. And an engaging portion 15 projecting inwardly. An internal thread portion 16 that can be screwed into the external thread portion 9 of the joint main body 3 is formed inside the intermediate portion of the nut 12, and a distal end portion of the nut 12 is formed as a jacket cylinder 17. An abutting surface 18 and a pressing surface 19 are formed between the base portion and the intermediate portion of the nut 12 and between the intermediate portion and the distal end portion.
[0017]
The sliding member 20 is made of a synthetic resin having a low friction coefficient such as PTFE (polytetrafluoroethylene resin), PFA (perfluoroalkoxy resin), polyamide resin, polybutylene terephthalate resin, and the like, as shown in FIGS. Formed as a continuous ring as a whole, the outer peripheral surface becomes an annular surface substantially parallel to the axis, the rear end surface becomes a surface substantially perpendicular to the axis, and the inner side gradually becomes smaller in diameter from the front end toward the rear end side. The tapered engagement surface 21 is formed so that the rear side of the engagement surface 21 is substantially parallel to the axis. The sliding member 20 is accommodated in the accommodating recess 13 of the nut 12, the outer peripheral surface is bonded to the stepped portion 14 with the adhesive 22, the rear end surface is engaged with the engaging portion 15, and the sliding member 20 is advanced integrally with the nut 12. It has become so. The nut 12 and the sliding member 20 are fitted to the outer periphery of the stainless steel pipe 1 in a loose state so as to be movable along the axial direction.
[0018]
The colored stop ring 23 is made of polyacetal resin or the like, and in particular, as shown in FIGS. 4 (a) and 4 (b), protrudes in the axial direction at substantially equal angular intervals on one side outer periphery of the ring-shaped portion 24. The part 25 is provided integrally, and one part of the ring-shaped part 24 is cut off by the cut-off part 26, elastically deformed by an external force, the diameter is expanded, and the external force is removed so that the diameter is restored to be reduced. It has become. The stop ring 23 has a ring-shaped portion 24 accommodated in the receiving groove 11 of the joint body 3, and the protruding portion 25 is fitted to the male screw portion 9 on the outer periphery of the male screw portion 9 near the receiving groove 11. Are combined. At this time, since the stop ring 23 can be expanded by the separating portion 26 as described above, the ring-shaped portion 24 can be easily passed through the male screw portion 9 and easily received in the receiving groove 11.
[0019]
Then, in a state where the nut 12 is fitted to the stainless steel pipe 1, the female thread portion 16 is screwed to the male thread portion 9 of the joint main body 3, whereby the inclined engagement surface 21 of the sliding member 20 causes the annular shape of the stainless steel pipe 1. The stainless steel pipe 1 can be advanced by pressurizing the remote side of the protrusion 2 with respect to the pipe end. Accordingly, the tube end side portion of the annular projecting portion 2 of the stainless steel pipe 1 is brought into pressure contact with the O-ring 8 to pressurize the O-ring 8 toward the bottom side of the receiving recess 7, and the O-ring 8 is moved to the receiving recess 7. The bottom part and the pipe end side part of the annular projecting part 2 can be compressed in an inclined direction with respect to the joint body 3 and the axis of the stainless steel pipe 1.
[0020]
Further, when the nut 12 is tightened into the joint body 3, in the case of manual tightening, the protruding portion 25 is not deformed from the state in which the pressing surface 19 is in contact with the protruding portion 25 of the stop ring 23. The stainless steel pipe 1 cannot be advanced by the member 20, and in the case of final tightening with a tool, the protruding portion 25 of the stop ring 23 can be deformed by the pressing surface 19, that is, the stainless steel by the nut 12 and the sliding member 20. It is set so that the steel pipe 1 can be advanced as described above. The deformed protrusion 25 is concealed inside the outer casing 17 of the nut 12. Further, the stainless steel pipe 1 is advanced by the nut 12 and the sliding member 20 as described above, and the base portion at the pipe end side portion of the annular projecting portion 2 in the continuous state where the O-ring 8 is compressed is the insertion portion 4 of the joint body 3. The contact portion 18 of the nut 12 is brought into contact with the distal end surface of the joint body 3 so as to be brought into contact with the corner portion 27 with the expanded portion 6 in a pressurized state.
[0021]
In the above configuration, the connection operation between the stainless steel pipe 1 and the joint body 3 will be described below. First, as shown in FIG. 1, one or two nuts 12 and a sliding member 20 are fitted to the stainless steel pipe 1, and at one end or both ends of the stainless steel pipe 1, slightly inward from the pipe end. As described above, the pipe expanding process is performed to expand the pipe diameter, and the annular protrusion 2 having an arcuate cross section is formed. Next, the tip of the annular projecting portion 2 in the stainless steel pipe 1 is inserted into the insertion portion 4 of the joint body 3. Next, the nut 12 fitted to the stainless steel pipe 1 is manually rotated together with the sliding member 20 so that the female thread portion 16 of the nut 12 is screwed to the male thread portion 9 of the joint body 3 and The positioned pressing surface 19 is brought into contact with the front end surface of the protruding portion 25 of the stop ring 23.
[0022]
Next, the nut 12 is tightened together with the sliding member 20 using a tool as shown in FIG. 2, and the protrusion 25 of the stop ring 23 is pressed and crushed by the pressing surface 19 of the nut 12. The stainless steel pipe 1 is advanced by pressing the separation side portion with respect to the pipe end of the annular protrusion 2 of the stainless steel pipe 1 by the mating surface 21. As the stainless steel pipe 1 advances, the O-ring 8 is pressurized against the bottom of the housing recess 7 at the pipe end side of the annular protrusion 2 of the stainless steel pipe 1, and the base on the pipe end side of the annular protrusion 2 is connected to the joint. Press contact with the corner 27 of the main body 3. Here, the sum of the frictional resistance to the O-ring 8 on the tube end side portion of the annular projecting portion 2 and the frictional resistance to the corner portion 27 is the separation side portion with respect to the tube end of the engagement surface 21 of the sliding member 20 and the annular projecting portion 2. When the nut 12 is rotated together with the sliding member 20 and the nut 12 is fastened to the joint body 3, it is possible to prevent the stainless steel pipe 1 from rotating together.
[0023]
In this manner, the female threaded portion 16 of the nut 12 is screwed into the male threaded portion 9 of the joint body 3 until the abutment surface 18 of the nut 12 contacts the distal end surface of the joint body 3. 2, the O-ring 8 is compressed in an inclined direction with respect to the axis of the joint body 3 and the stainless steel pipe 1 between the pipe end side and the bottom of the housing recess 7, so that the joint body 3 and the stainless steel pipe 1 are completely sealed. And leakage of the fluid flowing in the stainless steel pipe 1 can be prevented. When the stainless steel pipe 1 and the joint body 3 are connected in this way, the O-ring 8 is strongly pressed on almost two surfaces of the bottom of the receiving recess 7 and the pipe end side portion of the annular projecting portion 2. The compression set is small and can be sufficiently restored. Therefore, the seal between the stainless steel pipe 1 and the joint body 3 can be secured semipermanently, and the sealability is extremely excellent.
[0024]
Moreover, in the connection operation | work of the stainless steel pipe 1 and the coupling main body 3, as for the nut 12 being tightened reliably and whether it connected, the parallel protrusion part 25 of the colored stop ring 23 shows in FIG. Thus, the nut 12 is crushed by the pressing surface 19 and concealed inside the jacket cylinder 17 so that it can no longer be seen, so that the nut 12 is securely tightened and confirmed to be securely connected. Can do.
[0025]
Even if the stainless steel pipe 1 not pipe-expanded in the joint body 3 is piped by the carelessness of the operator, the gap between the inner circumference of the O-ring 8 and the outer circumference of the stainless steel pipe 1 not pipe-expanded as described above. Since there is a gap (see Fig. 1), a water leak occurs during the water pressure test after piping construction, so it can be repaired immediately by repair work.
[0026]
And after piping construction, a water pressure (pneumatic pressure) test is performed and the seal inspection of the connecting portion between the stainless steel pipe 1 and the joint body 3 is performed, and when connected in a complete seal state as described above, Water (air) does not leak, but in the event that there is a defect such as forgetting to tighten the nut 12, it passes through the gap between the inner peripheral surface of the O-ring 8 and the outer peripheral surface of the stainless steel pipe 1 shown in FIG. Since water (air) leaks to the outside, incomplete piping connections can be found and complete piping connections can be made.
[0027]
In the first embodiment, since the sliding member 20 is integrally provided in the accommodation recess 13 of the nut 12 by bonding, the sliding member 20 is dropped from the nut 12 when the stainless steel pipe 1 is inserted into the nut 12. Therefore, the piping work can be performed smoothly and quickly.
[0028]
Next, a second embodiment of the present invention will be described. FIG. 5 shows a pipe joint according to the second embodiment of the present invention, and is a cross-sectional view of the main part before connection. FIG. 6 is a cross-sectional view of the main part in the state after connection, showing the pipe joint. (a) and (b) are a front view and a right side view, respectively, showing a sliding member used for the pipe joint.
[0029]
The present embodiment differs from the first embodiment in the configuration in which the sliding member 20 is provided integrally with the nut 12 and is the same in the other configurations. Thus, the description thereof is omitted, and different configurations are mainly described.
[0030]
In the present embodiment, as shown in FIGS. 5 to 7, an accommodation recess 28 formed of an annular groove is formed inside the base of the nut 12. On the other hand, the sliding member 29 is made of a synthetic resin having a low friction coefficient, and is formed in a ring shape as a whole. The sliding member 29 has a cut-off portion 30 at one location, and is elastically deformed by an external force to reduce its diameter, thereby removing the external force. It becomes the structure restored so that a diameter may be expanded by being deviated. The sliding member 29 is formed such that the outer peripheral surface, the front end surface, and the rear end surface thereof can be adapted to the shape of the receiving recess 28, and the inner side gradually decreases in diameter from the front end toward the rear end side. The engagement surface 31 is formed so that the rear side of the engagement surface 31 is substantially parallel to the axis. The sliding member 29 is reduced in diameter by elastic deformation due to external force, and is inserted into the receiving recess 28 of the nut 12 from the front side of the lower protruding portion, and is expanded in the receiving recess 28 by removing the external force. It is held so as not to leave.
[0031]
Then, in the state where the nut 12 and the sliding member 29 are loosely fitted to the stainless steel pipe 1, the female screw portion 16 of the nut 12 is screwed into the male screw portion 9 of the joint body 3, whereby the sliding member 29 is inclined. The engagement surface 31 pressurizes the separation side portion of the annular projecting portion 12 of the stainless steel pipe 1 with respect to the pipe end to advance the stainless steel pipe 1, and the joint body 3 and the stainless steel pipe 1 are connected to each other as in the first embodiment. It can be connected in a sealed state.
[0032]
Also in this embodiment, the sum of the frictional resistance with respect to the O-ring 8 on the tube end side portion of the annular protrusion 2 and the frictional resistance with respect to the corner portion 27 is relative to the engagement surface 31 of the sliding member 29 and the tube end of the annular protrusion 2. By setting it to be larger than the frictional resistance with the separated side portion, it is possible to prevent the stainless steel pipe 1 from rotating together when the nut 12 is rotated and the nut 12 is fastened to the joint body 3. In particular, the sliding member 29 can be rotated with respect to the nut 12 by housing the sliding member 29 in the housing recess 28 formed of an annular groove in the nut 12 and holding it in the nut 12 as in this embodiment. In addition, the frictional resistance when the remote side of the annular projecting portion 2 of the stainless steel tube 1 is pressed through the sliding member 29 when the nut 12 is fastened to the joint body 3 can be further reduced.
[0033]
In addition, also in the said 1st Embodiment, the sliding member 20 can be comprised so that it may have a cutting part in one place similarly to the said 2nd Embodiment. Further, in both the first and second embodiments, the sliding members 20 and 28 can be configured in a split mold such as a split mold. Further, the sliding member 29 in the second embodiment can be housed in the housing recess 28 formed of an annular groove and can be provided integrally with the nut 12 by bonding. Further, the sliding member 29 can be formed in an annular shape without being divided. In this case, for example, if one of the wall portions forming the accommodation recess 28 is screwed to the nut 12, the sliding member 29 is formed. Can be easily accommodated in the accommodation recess 28. Further, the sliding member 20 in the first embodiment may be simply accommodated without adhering to the accommodation recess 13. Further, the friction resistance between the pipe end side portion and the sealing material in the annular projecting portion 2 of the stainless steel pipe 1 is set to be larger than the friction resistance between the separation side portion and the sliding members 20 and 28 with respect to the tube end in the annular projecting portion 2. By doing so, it is not necessary to press the tube end side portion of the annular projecting portion 2 to the corner portion 27 of the joint body 3. Further, the sealing material such as the O-ring 8 is accommodated in an accommodation recess whose front end is opened, and this sealing material may be pressurized not only by the annular projecting portion 2 of the stainless steel pipe 1 but also by the contact surface 18 of the nut 12. it can. In addition, the present invention can be variously modified without departing from the basic technical idea.
[0034]
【The invention's effect】
As described above, according to the present invention, the end portion of the metal tube is inserted into the joint body, the female thread portion of the nut fitted to the metal tube is screwed into the male thread portion of the joint body, The metal tube is advanced by pressurizing the separation side portion with respect to the tube end of the annular projection of the metal tube through the provided sliding member, and at the same time, at least the tube end side portion of the joint body and the annular projection of the metal tube And pressurizing the sealing material to connect the metal tube and the joint body in a sealed state. Thus, when a metal tube having an annular protrusion at the end is connected to the joint body in a sealed state using a nut, the metal tube is advanced with respect to the joint body via the sliding member. It is possible to prevent turning. Therefore, it is possible to prevent loosening of a nut or the like screwed on the other side of the joint body or damage of the sealing material, and improve connection reliability.
[0035]
Also, by providing the sliding member integrally with the nut or holding it so as to prevent detachment, it is possible to prevent the sliding member from dropping or losing when the metal pipe is inserted into the nut, and therefore, the connecting work is smooth. And can be done quickly.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part in a state before connection, showing a pipe joint according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of an essential part showing the pipe joint in a state after connection.
FIGS. 3A and 3B are a front view and a right side view showing a sliding member used in the pipe joint, respectively.
FIGS. 4A and 4B are a front view and a right side view showing a stop ring used for the pipe joint, respectively.
FIG. 5 shows a pipe joint according to a second embodiment of the present invention and is a cross-sectional view of a main part in a state before connection.
FIG. 6 is a cross-sectional view of an essential part showing the pipe joint in a state after connection.
7A and 7B are a front view and a right side view showing a sliding member used for the pipe joint, respectively.
[Explanation of symbols]
1 Stainless steel pipe (metal pipe)
2 Annular protrusion 3 Joint body 8 O-ring (seal material)
12 Nut 13 Housing recess 20 Sliding member 21 Engaging surface 23 Stop ring 28 Housing recess 29 Sliding member 31 Engaging surface

Claims

A pipe joint for connecting a metal pipe having an annular projecting portion that gradually becomes larger in diameter from the pipe end side to the remote side and that gradually becomes smaller in diameter following the large diameter part ,
A joint body having an external thread on the outer periphery of the end;
A nut having a female thread portion that is fitted to the outer periphery of the metal tube and is screwed into the male thread portion of the joint body;
The sliding member receiving recess that is released forward in the tube insertion direction inside the nut is provided so as to be able to advance integrally with the nut, and the taper that gradually becomes smaller in diameter from the front end side toward the rear end side. And the outer and rear end sides thereof are supported by the sliding member receiving recesses, and the female threaded portion of the nut is screwed into the male threaded portion of the joint body, whereby the annular projecting portion of the metal tube A resin-made sliding member that pressurizes the separation side with respect to the tube end to advance the metal tube;
It is fitted in a seal housing recess formed on the inner surface of the joint body, and in a compressed state between at least the joint body and the pipe end side portion of the annular projection of the metal pipe as the metal pipe advances. is interposed, the outer and the tube end side Ru is supported on the seal housing recess, and a sealing member,
When the nut and the joint main body are combined on the outside of the tube, a seal material is provided on the tube end side of the annular projecting portion outside the tube, and a sliding member is provided on the outer side of the tube and on the remote side of the annular projecting portion. Is abutted,
The seal material is pressed against the pipe end side of the annular projecting portion by being pushed inward and away from the seal receiving recess by the axial compressive force due to the joint between the nut and the joint body. Pipe fittings.

Fitted to the end of the male threaded portion of the joint body, hinders manual tightening of the nut, has a projecting portion that deforms during final tightening with the tool of the nut, and when the final tightening with the tool of the nut, The pipe joint according to claim 1, further comprising a stop ring concealed inside the tip of the nut.

The pipe joint according to claim 1 or 2, wherein the sliding member is integrally provided on the nut by bonding.

The pipe joint according to claim 1 or 2, wherein the sliding member is fitted into a groove-like accommodation recess of the nut and held by the nut.

The pipe joint according to claim 1 or 2, wherein the sliding member is fitted in and bonded to the groove-like accommodation recess of the nut and is provided integrally with the nut.

The pipe joint according to any one of claims 1 to 5, wherein the sliding member is formed in a continuous ring shape.

6. The sliding member according to claim 1, wherein the sliding member has a cut-off portion at one location, and is formed into a ring shape that is elastically deformed by an external force to reduce the diameter and is restored so that the diameter is enlarged by removing the external force. A pipe joint according to any one of the above.

The joint body has a seal material accommodation recess in the widened portion of the end, the seal material is housed in the seal material accommodation recess, and the female thread portion of the nut is screwed into the male thread portion of the joint body. By pressurizing the separation side portion of the annular projection of the metal tube with respect to the tube end by the sliding member inside the nut, the tube end side portion of the annular projection is pressurized to the sealing material, and the joint body is expanded. The pipe joint according to any one of claims 1 to 6, wherein the pipe joint is configured to pressurize a proximal end portion of the portion.